World Cup: What Is That Foaming Spray Used by Refs?

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If you're watching the FIFA World Cup this year, you may have
seen a free kick where the referee took out a spray can and
proceeded to draw a line on the grass in front of the players.

No, it's not shaving cream. It's "vanishing spray," an
aerosolized substance that provides a temporary visual aid to
ensure that, during a free kick, the defenders and the kicker
don't encroach on the 10-yard (9.1 meters) separation mandated by
game regulations.

The tendency for the wall of defenders to creep forward during a
free kick is a common cause of dispute in the beloved ballgame.
Referees carry the spray with them, but are not required to use
it. However, players must abide by the 10-yard regulation with or
without the spray, according to regulations.

Argentinian journalist and entrepreneur Pablo Silva developed a
commercial version of the spray called "9:15 Fairplay," a
reference to the metric equivalent of the free-kick distance
requirement.

"We find the vanishing spray to be extremely useful and very
effective in ensuring the defenders are 10 yards from the ball,"
Paul Rejer, training and development manager for
the Professional Referees Organization, told CNN.

The
vanishing spray contains a mixture of butane, isobutane
and propane gas; a foaming agent; water; and other chemicals.
When it leaves the can, the gas depressurizes and expands,
creating small, water-covered droplets on the field. The butane
mixture later evaporates, leaving only water and surfactant
residue behind.

Use of the spray at the World Cup ignited quite a buzz on
Twitter. "Please tell me I'm not the only one with [a] strange
fascination with the magical spray paint [they] use before free
kicks," tweeted @EmmaBlahh. "It wasn't the
vanishing spray [I] was impressed with, it was more the
flamboyancy with which it was administered," tweeted @MickCityTalk.

The foaming spray is one of several innovations at this year's
World Cup. Other new tech includes a
robotic exoskeleton that was showcased at the
tournament's opening ceremony, new goal-line technology and
perhaps the
most advanced soccer ball ever developed.